package com.android1608.administrator.encrption;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.util.Base64;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

//对称加密
//DES(8位),AES(16位),3DES(32位)
public class MainActivity extends AppCompatActivity {
    private EditText input,pw;
    private TextView showInfo;
    //加密的结果
    String encryptResult = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();
    }

    private void initView() {
        input = (EditText) findViewById(R.id.input);
        pw = (EditText) findViewById(R.id.pw);
        showInfo = (TextView) findViewById(R.id.showInfo);
    }

    public void encrypt(View view) {
        String data = input.getText().toString().trim();
        String pw = this.pw.getText().toString().trim();

        //解密的结果
        String decryptResult = null;
        switch (view.getId()){
            case R.id.desEncrypt://DES加密
                encryptResult = encrypt("DES",data,pw);
                showInfo.setText("DES加密的内容是："+data+"加密结果是："+encryptResult);
                break;
            case R.id.desDecrypt://DES解密
                 decryptResult = decrypt("DES",encryptResult,pw);
                showInfo.setText("DES解密结果是："+decryptResult);
                break;
            case R.id.desedeEncrypt://3DES加密
                encryptResult = encrypt("DESede",data,pw);
                showInfo.setText("3DES加密的内容是："+data+"加密结果是："+encryptResult);
                break;
            case R.id.desedeDecrypt://3DES解密
                decryptResult = decrypt("DESede",encryptResult,pw);
                showInfo.setText("3DES解密结果是："+decryptResult);
                break;
            case R.id.aesEncrypt://AES加密
                encryptResult = encrypt("AES",data,pw);
                showInfo.setText("AES加密的内容是："+data+"加密结果是："+encryptResult);
                break;
            case R.id.aesDecrypt://AES解密
                decryptResult = decrypt("AES",encryptResult,pw);
                showInfo.setText("AES解密结果是："+decryptResult);
                break;
        }
    }

    private String decrypt(String type, String data, String pw) {
        switch (type){
            case "DES":
                //1 获取解密对应的类,解密引擎
                try {
                    Cipher cipher = Cipher.getInstance(type);
                    //2 对解密引擎进行初始化
                    if (pw.getBytes().length!=8){
                        throw new Exception("密码长度必须8位");
                    }
                    Key key = new SecretKeySpec(pw.getBytes(),type);
                    cipher.init(Cipher.DECRYPT_MODE,key);
                    //3 执行解密
                    if (!TextUtils.isEmpty(data)){
                       //Base64的逆运算
                        byte[] base64Decode = Base64.decode(data.getBytes(), Base64.DEFAULT);
                        byte[] decryptBytes = cipher.doFinal(base64Decode);

                        return new String(decryptBytes);
                    }

                } catch (NoSuchAlgorithmException e) {
                    e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                    e.printStackTrace();
                } catch (InvalidKeyException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                break;
            case "DESede":
                //1 获取解密对应的类,解密引擎
                try {
                    Cipher cipher = Cipher.getInstance(type);
                    //2 对解密引擎进行初始化
                    if (pw.getBytes().length!=24){
                        throw new Exception("密码长度必须24位");
                    }
                    Key key = new SecretKeySpec(pw.getBytes(),type);
                    cipher.init(Cipher.DECRYPT_MODE,key);
                    //3 执行解密
                    if (!TextUtils.isEmpty(data)){
                        //Base64的逆运算
                        byte[] base64Decode = Base64.decode(data.getBytes(), Base64.DEFAULT);
                        byte[] decryptBytes = cipher.doFinal(base64Decode);

                        return new String(decryptBytes);
                    }

                } catch (NoSuchAlgorithmException e) {
                    e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                    e.printStackTrace();
                } catch (InvalidKeyException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                break;
            case "AES":
                //1 获取解密对应的类,解密引擎
                try {
                    Cipher cipher = Cipher.getInstance(type);
                    //2 对解密引擎进行初始化
                    if (pw.getBytes().length!=16){
                        throw new Exception("密码长度必须16位");
                    }
                    Key key = new SecretKeySpec(pw.getBytes(),type);
                    cipher.init(Cipher.DECRYPT_MODE,key);
                    //3 执行解密
                    if (!TextUtils.isEmpty(data)){
                        //Base64的逆运算
                        byte[] base64Decode = Base64.decode(data.getBytes(), Base64.DEFAULT);
                        byte[] decryptBytes = cipher.doFinal(base64Decode);

                        return new String(decryptBytes);
                    }

                } catch (NoSuchAlgorithmException e) {
                    e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                    e.printStackTrace();
                } catch (InvalidKeyException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                break;
            default:
                try {
                    throw  new Exception("类型错误");
                } catch (Exception e) {
                    e.printStackTrace();
                }
                break;
        }

        return null;

    }

    private String encrypt(String type, String data, String pw) {
        switch (type){
            case "DES":
                //1 获取加密对应的类,加密引擎
                try {
                    Cipher cipher = Cipher.getInstance(type);
                    //2 对加密引擎进行初始化
                    if (pw.getBytes().length!=8){
                        throw new Exception("密码长度必须8位");
                    }
                    Key key = new SecretKeySpec(pw.getBytes(),type);
                    cipher.init(Cipher.ENCRYPT_MODE,key);
                    //执行加密
                    if (!TextUtils.isEmpty(data)){
                        byte[] encryptBytes = cipher.doFinal(data.getBytes());
                        byte[] base64Encode = Base64.encode(encryptBytes, Base64.DEFAULT);
                        return new String(base64Encode);
                    }

                } catch (NoSuchAlgorithmException e) {
                    e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                    e.printStackTrace();
                } catch (InvalidKeyException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }


                break;
            case "DESede":
                //1 获取加密对应的类,加密引擎
                try {
                    Cipher cipher = Cipher.getInstance(type);
                    //2 对加密引擎进行初始化
                    if (pw.getBytes().length!=24){
                        throw new Exception("密码长度必须24位");
                    }
                    Key key = new SecretKeySpec(pw.getBytes(),type);
                    cipher.init(Cipher.ENCRYPT_MODE,key);
                    //执行加密
                    if (!TextUtils.isEmpty(data)){
                        byte[] encryptBytes = cipher.doFinal(data.getBytes());
                        byte[] base64Encode = Base64.encode(encryptBytes, Base64.DEFAULT);
                        return new String(base64Encode);
                    }

                } catch (NoSuchAlgorithmException e) {
                    e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                    e.printStackTrace();
                } catch (InvalidKeyException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                break;
            case "AES":
                //1 获取加密对应的类,加密引擎
                try {
                    Cipher cipher = Cipher.getInstance(type);
                    //2 对加密引擎进行初始化
                    if (pw.getBytes().length!=16){
                        throw new Exception("密码长度必须16位");
                    }
                    Key key = new SecretKeySpec(pw.getBytes(),type);
                    cipher.init(Cipher.ENCRYPT_MODE,key);
                    //执行加密
                    if (!TextUtils.isEmpty(data)){
                        byte[] encryptBytes = cipher.doFinal(data.getBytes());
                        byte[] base64Encode = Base64.encode(encryptBytes, Base64.DEFAULT);
                        return new String(base64Encode);
                    }

                } catch (NoSuchAlgorithmException e) {
                    e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                    e.printStackTrace();
                } catch (InvalidKeyException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }

                break;
            default:
                try {
                    throw  new Exception("类型错误");
                } catch (Exception e) {
                    e.printStackTrace();
                }
                break;
        }

        return null;
    }
}
